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Bitmapped Images
27th November 2014
With Mrs Billinghurst
@SGS_Computing
Bitmapped Images27th November 2014
Key Terms:PixelBitmapResolutionColour Depth
Bitmapped Images27th November 2014
PixelThe smallest area of an image.
Each square in this image represents one pixel
Bitmapped Images27th November 2014
BitmapA grid of pixels which in which the position of coloured pixels are mapped in a grid.
Bitmapped Images27th November 2014
ResolutionThis is the number of pixels that make up an image or screen.
width x height
Bitmapped Images27th November 2014
Colour Depth
The number of bits used to represent the colour of a single pixel in a bitmap.
Bitmapped Images27th November 2014
Colour Depth : 1 Bit (2 colours)
White = 0Black = 1
This image is 32 pixels wide.How many bytes are needed per row? 8 bytes
Bitmapped Images27th November 2014
Colour Depth : 2 Bit (4 colours)
White = 00Black = 01
Yellow = 10Green = 11
This image is 32 pixels wide.How many bytes are needed per row? 16 bytes
Bitmapped Images27th November 2014
Colour Depth : 3 Bit (8 colours)
White = 000Black = 001
Yellow = 010Green = 011Brown = 100
Tan = 101Blue = 110
Light Green = 111
Bitmapped Images27th November 2014
Also known as monochrome.
One bit is allocated to each pixel = black & white
1 Bit Colour
Bitmapped Images27th November 2014
Each of the RGB components of a colour is given a nibble:
12 Bit Direct Colour
Bitmapped Images27th November 2014
This simulates the colours that a human eye can see
Holding 16.7 million different colours
24 Bit True Colour
Bitmapped Images27th November 2014
This is really just 24 bit colour with an extra 8 bits.
32 Bit Colour
Why? Modern computers work in either 32 or 64 bits (or the additional 8 bits provide transparency)
Bitmapped Images27th November 2014
Bitmapped Images27th November 2014
Bitmapped Images27th November 2014
Bitmapped Images27th November 2014
Each pixel is stored as a binary number.
OR
Each pixel is stored as a bit pattern / RGB bits
Bitmapped Images27th November 2014
8(or 1 byte)128 64 32 16 8 4 2 1
1 1 1 1 1 1 1 1
Bitmapped Images27th November 2014
Key Terms:PixelBitmapResolutionColour Depth
Bitmapped Images
27th November 2014
With Mrs Billinghurst
@SGS_Computing
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